The present invention relates to optical waveguide fibers but in particular to buffered optical waveguide fibers suitable for optical waveguide cable construction.
Optical waveguides are a relatively new development and no significant commercial use has taken place to date. In view of this, optical waveguide cable construction is a new art. Some of the problems encountered in optical waveguide cable construction are as follows. To provide useful optical waveguides, signal attenuation must be low and preferably about 10 db/kilometer or less. Optical waveguides transmit visible or invisible light. In the transmission of such light signals, they are readily attenuated in response to relatively small distortion of the optical waveguide. For example, relatively sharp bends, or a rough adjacent surface may produce sufficient distortions within the optical waveguide to result in totally unacceptable signal attenuation. Similarly, transverse or longitudinal stresses imposed upon the optical waveguide fibers during cable construction or inherent in the resulting structure may produce totally unacceptable signal attenuation in the resulting cable. These and many other problems have been encountered in producing an acceptable optical waveguide cable. In view of this, preparation of prior art fibers or wires for cable manufacture, has been found to be totally unacceptable.
For a better understanding of optical waveguide fibers and their manufacture, reference is made to the following U.S. patents: U.S. Pat. No. 3,659,915 issued to R. D. Maurer and P. C. Schultz; U.S. Pat. No. 3,711,262 issued to D. B. Keck and P. C. Schultz; U.S. Pat. No. 3,737,292 issued to D. B. Keck, P. C. Schultz and F. Zimar; U.S. Pat. No. 3,775,075 issued to D. B. Keck and R. D. Maurer; and U.S. Pat. No. 3,823,995 issued to L. L. Carpenter.